Retractable landing gear for amphibian airplanes



Nov. 18, 1947. E. E. WALLACE RETRACTABLE LANDING GEAR FOR AlVlPX-IIBIANAIRPLANES Filed Aug. s, 1944 a Sheets-Sheet 1 QN N B mm m W I I L I V H.0m N v KN. H u: 7 K

Nov. 18, 1947. E. E. WALLACE RETRACTABLE LANDING GEKR FOR AMPHIBIANAIRPLANES Filed Aug. 5, 1944 8 Sheets-Sheet 2 INVENTOR,

Nov. 18, 1947". E; WALLA E 2,430,898

RETRACTABLE LANDING GEAR FOR AMPHIBIAN AIRPLANES Filed Aug. 3, 1944 8Sheets-Sheet 5 "IVE/W012.

E. E. WALLACE Nov. 18, 1947.

RETRACTABLE LANDING GEAR FOR AMPHIBIAN AIRPLANES 3, 1944 8 Sheets-Sheet4 Filed Aug mmrme. flmmo 51 11 4114::

RETRACTABLE LANDING GEAR FOR AMPHIBIAN AIRPLANES Filed Aug. 3, 1944 aSheets-Sheets IN VEN TOR.

Nov. 18-, 1947. .E. E. WALLACE 2,430,393

RETRACTABLE LANDING GEAR FOR AMPHIBIAN AIRPLANES.

Filed Aug. s, 1944 a Sheets-Sheet 6 um 0E xmw mw FIUW HI a INVENTOR.

I I I r M f. M

Nov. 18, 1947. E. E. WALLACE RETRACTABLE LANDING GEAR FOR AMPHIBIANAIRPLANES Filed Aug. 3, 1944 8 Sheets-Sheet 7 Nov. 18, 1947. I v E. E.WALLACE 2,430,898

RETRACTABLE LANDING GEAR FOR AMPHIBIAN AIRPLANES Filed Aug. 3, 1944 8Sheets-Sheet 8 fatenteci Nov. 18, 1947 UNITED STATES. PATENT QFFICE R TRTAB E LANDING GEAR. FOB AMPHIBIAN AIBPLANES Edward E. Wallace, CieveltmdHeights, Ohio nn ieafiqn ugust: 3, 4 Se i l Nd- 541,370

o. 31,102, filed ebruary 16 1942, flow matureq int at nt 2 415, 1

'obje 't of th nven i n is to pr de an i, 11 Kid pl ne li in a i e rstravt ible Into" the Wine structures thereof an simph find ew 'r" m ansfer o e in e gears to end hJe' 6: th in nt ve is t? ens iet imbreveq ail n e. ine struc ux s 9i whi h encl se f tr t bh andifl' gear the e fi etili iech ism fe ea h seer wheh it is ir; obe etlve positlon ro idinspac d, fixe l reiated su rts nd mp es ic d e between he a le" er its lnd n whe l nd thes s pports 0 h mit ela i mov nt tw en the Wine Str tu eand wheel long ud a l and l'ate elli el thelett rdurins landin e An t erbj ct o h invent on is t p viee Y a an r the e hi bien typ a g lendingg'eairs retraetible into the spjonsoris thefedf and ower means for eratng h 1 i 1= l' ars t0 an ro e r la idins t em and wherein provision ismade to house the gears and tfieif operating power means.

Aflothe ob et' of he n ion i to r v de m roveds r l s having laln'dihggears re ttaetible 1111120 the Wi g st uctures ri Power rfiea'nsbetweenthe landing gears for operating them arranged to oeoupy mifiimumspace in the fu ela nd wine str ctures. H

Qthe'r objects of the invention ill be apparefit to those Skilled in theart to which my i11- on e ates fr m t e ioll wi g desc ion taken nennect on with th e e me ny ne dyaiwirigs; wherein F g, I i a fragm aryw s o par n 'fi-gnt elevation and partly in section, a portion .oieairplan embo yin my e i Fig. 1g is e, fragmentary section on the linemeta 9f iet Fig. ,2 is a section on the line 2 2 pf Fig. 1;

Rig. ,3'is a View similar to Fig. 1, With the walls Of the fuselage and,sDonson broken away to Show t e landing ear in ret ct d position andthe new r m anism th e r;

Fi 3 is e se ti n th e 3 -3, 0 Fi .5;

Fig. 4 is a. section on the line 44 of Fig, 3;

Fi s. 2 and 3; partly in section'onthei 5 5 f i t Fig; 6 is a section onthe Iifie 6--6 of Fig; 1; Fig; ea is afi agihe teirjr seetiofi on theline Eel- 601 pfFig. 6;

Fig. '-7 is a} View similar to Fig.- i, but showing a modified form ofeenst-ructi m" Fig, 8 is a, view simiiar to Fig.- 3; with the walls atthe fuselge and, spon soribfokehaway to show the landing gear inretracted pos'itien' and the power mecha fiism thre'for, W

Fi Sci is asection on the line 811-811 of Fig; 8; Fig. 9 is aseetio'lion the Erie 9 9 of Fig; 8; ts. 3.0 is abottom plan View of pair-ts shownin Figs. 7 and 8,-part1-y r section on the'iirie |a |0 of Fi Figs. 11 m14, massive, are diagrammatic of the mounting for a. langlir g gearwhee} showing vat ious positio ris thereof inni glkihg la -lqiditigs;

Fig}- 15 is a) di'algfa'm showing the movement of the airplane undervarying landing eonditionsz In the drawings, [indicates as an entiretyan airplane having" a; fuselage [a and Wirig strum tures 2, preferablyof the construction shown m gsfoiesa id application; where'm tiie Wingstridesures eonsist of airfeils s and 1. D e to the fact that thesestructural met-fibers and the lahdin g geirsat opposite sides of thefuselage m ztre similar in onstr'uction, the illustrations in thedrawings have been restrieted to a portion ef the plane,- including e,portion of the fiiselalge, ail-foiland a propl lef 1:16,- es the enginefor the latte? is moimt'ed on the adjacent airfoil 6. Acidordingly,ye-ferenee will be made to ofrly' ene of these members, As shownin Fig;1, the fuse} lage La provides p ymae spaces ix having'ufiper' aridIow'er floors [331, la". The exteriof'wal lsf of the fuselage Ia;airfoil 6 and spbnsjoh 'I are formed of suitahle sheet material withsuitable tiilss, bracing and reihforcemez t elements, certain of whichare shown and will bereferred to? these em nts f r th s n o h ns a ra edto r ide f r a cham 9 .c mnerfim nt 8 which receives and eol pletelyeneloses the adjaeent la n gear, indicated as an en r t r t 9 as sho'yyhin Figs. 3 and 5 As illustrated, the side ehgl hottomwa'hs oitheeotnpartment 8 are suit} a l s orted wi hin th a a n s nsq 1 i,reletijqn stoxan opening 84 prjovigled in the bottom wal hereqi, wh ebythe l ndin ea 9 m '9 swung to an; operative position (seeFigs. 1 afid 2)when the airplane is to take off from or land on land.

When the airplane is in flight, the landing gears 9 may be andpreferably are retracted into the compartments 8 to eliminate parasitedrag; they also occupy this position when landing and maneuvering on andtaking off from water. Doors II], Ii and I2 (later referred to) areprovided for closing and substantially sealing the compartment 8 afterthe adjacent landing gear is moved thereinto. The walls of thecompartment 8 and the inner walls of the doors are preferably shaped toclosely fit the adjacent landing gear 9, including its swinging devices,as later set forth, so that a minimum space in the compartment aroundthe landing gear exists for any water which may leak through or betweenthe joints for the doors Iii, II and I2 or between the latter and theside walls of the opening 8a.

The walls of the compartment 8 are suitably connected to the spars ofthe adjacent sponson and walls of the latter and fuselage so as toprevent leakage of water from the compartment into the sponson orfuselage, in the event water leak into the compartment through the jointof its closures.

Each landing gear 9 comprises a wheel I3 (preferabl of the pneumatictype), a mounting indicated as an entirety at 9 for the wheel swingablymounted at its inner end on and between spaced spars I5 within andextending longitudinally of the adjacent sponson 1 and an operatingmechanism, indicated as an entirety at It, for swinging the mounting 9in either direction, such mechanism also, by preference serving tooperate the doors I0, II and I2, so as to automatically close theopening So when the landing gear 9 is moved into the adjacentcompartment 8 and to automatically open the doors when the landing gearis moved to its operative position.

The wheel I3 is provided with a hub which rotates on a sleeve I3m'(suitable anti-friction bearings being provided between the hub andsleeve as shown in Figs. 1 and la) the sleeve being mounted on a shaftIT.

The opposite ends of the axle I! are secured to the lower endof themounting 9'. Of the mounting 9, I8 indicates an elongated, truss-likemember consisting of (a) a hollow bar or tube I9, the opposite ends ofwhich rotatably fit bushings 2E! suitably mounted in the spars I5 (seeFig, 2), to swingably mount the mounting 9 on the adjacent sponson (22)pairs of diverging hollow bars or tubes 2| (see Fig. 1), extending fromthe opposite outer end portions of the bar I9 in a direction inclinedtoward each other and (c) a hollow bar or tube 2| extending between andconnected to each bar 2| of one pair of bars and the corresponding bar2| of the other pair thereof. Plates 22 are secured (as by welding) tothe bars I9, 2| and 2| on the opposite lateral sides of the member I 8and to the outer sides of each pair of bars 2| at the opposite ends ofsaid member, and a plate 23 is secured (as by welding) to the bars 2|and 2| and plates 22, these plates serving to sealingly close the spacewithin the truss member I8 so as to reduce the water holding capacity ofthe adjacent compartment 8. The outer ends of each pair of bars 2|terminate in alined knuckles 20a, 20a, in which is mounted a cross pin24. Each pin 24 is fixedly secured, in any well known manner, to eitherone or both of the adjacent knuckles 28a, 20a, to prevent its rotation.23' indicates pairs of supporting members at opposite sides of the wheelI3 and connecting the opposite ends of the axle H to the truss memberI8. Each supporting member 23 consists of a plunger 23a, having on itsinner end a piston 23a (see Fig. 6) and a cylinder 231) into which theplunger telescopes. Each cylinder 23b is filled with air under pressurebelow the piston and oil under pressure above the piston (for example,air at approximately 500 lb. initial pressure per square inch and oilunder the same pressure as later set forth) to cushion the inwardmovement of the plunger. Also each plunger 23a is hollow and filled withoil having a pressure of approximately 500 lbs. per square inch. Eachplunger 23a and each cylinder 23b is provided with a valved device,whereby it may be filled with the fluid. Each device is similar inconstruction and similarly mounted. For example, the side wall of thecylinder is formed with a screw threaded opening in which is mounted theinner threaded end of a nipple 240 (see Fig. 6a), through which thecylinder may be charged with air (see Fig. 6). The bore through thenipple is shaped'to form a seat for a valve 24d (see Fig. 6a). The outerend of the nipple 240 is externally threaded to receive a removablescrew cap 24c, which may be tightened against a gasket 24c, which may betightened against a gasket 24a to seal the nipple. The outer end of eachplunger 23a is pivotally mounted on the end portion of the adjacent pin24, whereas the outer end of each cylinder 23b is pivotally connected tothe adjacent end portion of the axle H. The outer ends of the cylinderson the inner side of the wheel I3 are disposed between the adjacent sidewall I3x of the wheel I3 and a shoulder Ila on the adjacent end of theaxle I"! and the outer ends of the cylinders on the outer side of thewheel I3 are disposed between the sleeve I333 on the axle I1 and theinner end of a cap H, which has screw threaded engagement with theadjacent end of the axle H, the cap being preferably pinned to the axleafter the cylinders are mounted thereon. It will be observedthat, due tothe relative movements between the plungers 23a and their respectivecylinders 23b and the pivotal connections of the plungers to the trussmember I8 and pivotal connections of the cylinders to the axle I1, themounting 9 provides for relative vertical movements between the Wheel I3with respect to the truss-member I 8, as shown in Figs. 12, 12a, 12b,13, 13a, 13b, 14, 14a, 14b and 15, whereas the pivotal connection of themounting 9 with the spars I5 permits relative lateral movement of theairplane relative to the mounting and point of engagement of the wheelI3 with the ground, as shown in Figs. 11a, 12a, 12b, 13a, 13b, 14a, 14band 15, in directions substantially at right angles to the adjacentsponson I, whereby the wheel I3 yieldingly accommodates itself to forceswhich result in making a landing Or maneuvering on land to insure safetyand eliminate damages to the landin gear and airplane. Each supportingmember 23 at one side of the wheel I3 is connected to the correspondingsupporting member 23 on the opposite side of the wheel to insuresimultaneous relative telescoping movement of the plungers and cylindersof these connected-together members. For this purpose, the cylinder 23?)at each side of the wheel I 3 is provided with an inwardly extending rod25 alined with the rod 25 on the corresponding cylinder 23bat theopposite side of the wheel, and pivotally mounted on these rods 25 andthe adjacent pin 24 is a pair of links 26, 26a, pivotally connectedtogether at their inner ends (see Fig. 1a). As will be observed, as therods 25 extend into the knuckle for the link- 26'; the related members23' are tied to: gather in fixed relation. As shown in Figs. 1 and 3,-the knuckle for the link 26 has a Width substantially equal to thespacing of the adjacent cylinders 232), so as to engage therewith as thelink rocks on the rods 25, and thus maintain the links centrally of theadjacent Wheel I3. It will be observed that the supporting members 23'upon opposite sides of the wheel are disposed equal distances from animaginary plane which cuts the trunnion or bar l9 and center of thewheel (the central plane extending at right angles to the axle ll), sothat all forces against or transmitted through the wheel are always inline with the trunnion l9.

Each of the supporting members 23' is constructed to retard the movementof the plunger 23aou twardly-of the adjacent cylinder 2313. For thispurpose, the plunger 23a is of hollow construction (see Fig. 6) andfilled with liquid, such as oil a (under pressure as already set forth),which in the inward movement of the plunger and its piston, is forcedinto the cylinder 23b behind the piston 23a and in the outward movementof the plunger and its piston, the latter forces the liquid through arestricted by-pass back into the plunger, the restricted return flow ofthe liquid serving to prevent a rapid rebound of the parts connected tothe plunger 23a. The control of the liquid from the plunger 23a into thecylinder 23b and from the latter back into the plunger is provided forby the following devices: 230 indicates a rod axially supported in thecylinder 23b, its cuter end being threaded into an opening formed in theouter end Wall of the cylinder. The rod 23c extends through an openingformed in the piston 23a and is provided at its inner end with a head towhich is secured the outer end of a casing 23d. As shown in Fig. 6, thehead on the rod 230 is externally threaded and the casing 23d isinternally threaded, whereby these parts are adjustably connectedtogether and the casing fixedly supported relative to the cylinder 23b.By preference the piston 23a is formed with a recess 23a", whichaccommodates the lower end of the casing 2311 to permit a maximum strokeof the piston. The inner side wall of the recess 23a" is provided withscrew threads and the inner end of the plunger 23a is screw threaded toprovide a connection therebetween. The inner wall of the cylinder 23band adjacent its inner end is provided internally with screw threads fora closure 23?), which accommodates a suitable gland. As shown; when theparts are in normal position, a space is provided for a portion of theliquid at. The end wall of the casing 2301 is provided with a normallyclosed escape valve 236 for the liquid a, so that in the inward movementof the plunger 23a, the pressure of the liquid at therein will open theescape valve and permit the liquid to flow into the cylinder 231), thecasing 23d being formed with ports 23d to permit such flow of theliquid. The valve element of the escape valve 236 is normally biasedinto engagement with its seat by a coiled spring 23 surrounding theshank of the valve element and abutting the head thereof and the innerend of the head on the rod 230. As shown, the valve element of theescape valve 236 and its shank are formed with a through duct 23g whichforms a restricted by-pass for the liquid a in the return stroke of thepiston 23a to retard the movement of the plunger 23a. The duct 23g also6 permits flow of the liquid at to and from the plunger 23a when thelatter and the cylinder are in normal position to equalize the pressurethere in, the side wall of the plunger 2312 being formed with ports 23habove the piston 23a to provide a communication between the plunger 23dand cylinder 23b. The oil a is supplied to each plunger 23a through anipple 240 (see Fig. 6) which is similar in construction to the nipplethrough which air is supplied to the cylinder 23b.-

The mechanism 16 for swinging each mounting 9 and the Wheel l3 supportedthereby from the adjacent compartment 8 to its operative position and inthe reverse direction comprises a linkage 21 extending betweenandconnected to the adjacent side Wall la of the fuselage Id within eachsponso'n 1 arid-the adjacent mounting" 9' and power means 28' foroperating the linkage. The linkage for operating the mounting 9 isarranged to and operates in a vertical plane'- coincident withthe axisof the axle ll and at right angles; to the shaft 9. The linkage 2!includes compression devices 21x between it and the wheel mounting 9",which devices consist of the follow-- mg: 210, indicates a cylinderpivoted at its outer end by means of a universal joint on the inner endof the axle l1. 27b indicates a piston in the cylinder Zla carried onthe outer end of a lunger 29. The plunger 29, piston 21b, cylinder 21aand by-pass for the oil are similar in construction to the plunger 23a,piston 23a, cylinder 23!) and by-pass shown in Fig. 6, whereby inwardthrusts on the adjacent wheel I3 are cushioned and rebound thereofretarded. The inner end of the rod 29 is pivotally connected by means ofa uni: versal joint 29a to the linkage 21, that is, to the outer ends ofa pair of diverging rods 29b, 29b, forming elements thereof. The innerends of the rods 2912 are provided with knuckles which rotatably fit ashaft 290 (see Fig. 4). The opposite ends of the shaft 290 are mountedin bearings 29d suitably carried b the side wall Id of the fuselage lawithin the spo'nson 1. One element of the joint 29a consists of a pinZea on which pivot the outer ends of the rods 2%, 29b, and the outerends of a pair of rods 29a. The inner ends of the rods 29c are connectedby a pivot pin 29) to the inner end of a rod 29g, the outer end of Whichswings about a pivot pin or shaft 299' which is mounted in hollow bosseson a bracket 30 suitably fixed to the side wall Id of the fuselage lawithin the sponson l. The power means 28 comprise the following: 3!indicates a pair of spaced parallel thrust rods (see Fig. 5) pivotallymounted at their outer ends on the pin 29 at opposite sides of the rod29g and pivotally connected at their inner ends to pins did on theopposite sides of a nut 3H), which is mounted on the screw threadedportion of a shaft 32. The opposite ends of the shaft 32 are mounted insuitable bearings 32a provided on the inner sides of the Walls la of thefuselage la. A bearing 32b is also, by preference, provided for theshaft 32 intermediate it ends. 33 indicates a worm gear fixed to theshaft 32 adjacent one of the bearings 32a and in mesh with a worm 33a,suitably mounted in bearings 331). At one end, the shaft or shank of theworm 33a is provided with a sprocket to which power is transmitted by achain 330 engaging a sprocket suitably fixed to the shaft of a motor 34.As will be understood, the motor 34 may be driven in either direction torotate the shaft 32 in the desired direction to move the nut 3Iboutwardly or inwardly. As shown, the shaft 32 at one side of the bearing32b is provided with right hand screw threadsand at the opposite side ofthe bearing it is provided with'left hand screw threads, sothat byproviding a nut 39b on each screw threadedportion and connecting it tothe adjacent linkage 27, both landing gears 9 may be operatedsimultaneously totheir operative positions or to their retractedposition. When the landing gears 9 are in their retracted position (seeFigs. 3 and 5), the nuts 3lb are adjacent the bearings 321), so thatoperation of the shaft 32 counter-clockwise (as viewed in Fig. 2) willmove both nuts outwardly and efiect'outward movement of the rods 3|,which in turn will swing the rods 29b, 29c, 29g, to the position shownin Fig. 1 (as indicated by the lines a, b, c), to set the gears 9 inlanding position.

As shown in Figs. 1, 3, 3a and 5, the shaft 32 is mounted in a chamber32x which extends trans versely through the fuselage Ia and merges orcommunicates at its opposite ends with the compartments 8 in thesponsons l to accommodate portions of the linkage 2'5 and power means28. By preference, the floor la is formed with an opening to accommodatethe chamber 32:10 to mount the power means 28 in a plane belowzthe lowerfloor i a and the motor thereabove. The outer end walls of the chamber322: are suitably connected to the walls of the fuselage to preventintake of water into the latter. The chamber 3203 consists of a bottomwall 32m and the side and top walls 32x at each end thereof, the sidewalls converging upwardly (see Fig. 2) and the top wall being inclinedupwardly and laterally, whereby the outer ends of these walls areconnected to the walls la and substantially register with the inner openends of the compartments 8. Accordingly, when the doors for thecompartments 8 are closed, danger of water entering the chamber 321' iseliminated, but whatever leakage takes place is free to drain outthrough openings 35 (one only being shown in 1) when the airplane takesoff from the water.

The doors It), i l and I2 related to each sponson l are arranged toclose the adjacent compartment 8 to facilitate landing on water and toprevent the intake of water when the sponsons are in engagementtherewith. In closed position, the doors complete the bottom surface ofthe adjacent sponson to reduce parasite drag when the airplane is inflight or maneuvering on water. Due to the danger of intake of wateraround the edges of the doors when landing on water or the sponsons arein engagement therewith, I prefer to shape and relate the walls of eachcompartment 8 to closely fit over and around the wheel I3, its mounting9' and the devices for operating the wheel and mounting into and fromthe compartment, whereby, when these parts are in retracted position andthe doors 19, H and I2 are closed, minimum space exists within thecompartment to receive and hold water. Therefore it will be seen thatwhile the landing gears are carried in the sponsons and are operated atwill to landing and take-off position, provision is made for excludingwater from the sponsons when the landing gears are mounted in theirrespective compartments; furthermore, if intake of water takes place,the openings which permit such intake, will provide for drainage of thewater as soon as the plane is in fiight. The walls of each compartmentare shaped to form a cavity or recess 8a fitting over the wheel [3 andits mounting, diverging recesses 81) for the inner side members 23 ofthe mounting 9 and a recess 80 for the linkage 21, whereas the innerWall of the door 0 is shaped, as shown at [0:0, to take up the spacebelow the wheel between its axle and the adjacent wall Ia of thefuselage. e Each door I0 is interconnected to the adjacent linkage formovin the adjacent landing gear so as to move with the latter in eitherdirection and the adjacent doors II and I2 are interconnected to-theadjacent mounting 9' to swing therewith in either direction. Theseconnections form the subject matter, in part, of applicants co-pendingapplication, for which-reason no claim thereto is made herein.

Each door consists of inner and outer walls having suitable bracing andreinforcing elements between them.

As shown, the door I0 is mounted on the shaft 290; Intermediate its sideedges, the inner wall of the door I0 is shaped to form a recess Illa, toaccommodate the inner end of the rods 2%, which are pivotally mounted onthe shaft 290, as already set forth. One side wall of the recess Illa isprovided with spaced abutments 39, 39a, disposed upon opposite sides ofand in the path of movement of one of the rods 29b. Accordingly, whenthe power means are operated to operate the linkage 2i to move thelanding gear outwardly, the rod will engage the abutment 39a and swingthe door ID to its open position (see Fig. 1) and when the linkage 21 isoperated in the reverse direction the rod 291) will engage the abutment39 to swing the door ID with the landing gear. The abutment 39preferably comprises a spring which is put under tension as the rods 2%complete their closing movement. The spring 39 permits the door ID tomove relative to the cylinder 21a when operated by an initial dooroperating means (not shown) set for and claimed in the aforesaidco-pending application. As shown in Fig. 1, the free end of the door|0,'midway between its side edges, is provided with an extension Iflb(the adjacent edges of the door ll having a complementary recess toreceive the extension [811), in which is fixedly mounted a ring adaptedto telescope over the cap 11 on the extended outer end of the wheel axleIT, in the final movement of the door If! into closed position.

The door H is hingedly mounted on lugs llb carried by the adjacent bar2| of the truss member 18, whereas the door I2 is fixed to a shaft |2amounted in bearings provided in the spars 15. The inner cylinders of themounting 9 support pins 6| which fit into rings 8d, fixed to the wall ofthe compartment, whereas the door I2 is provided with rings 44 (only onebeing shown) which fit over the extended ends of the rods 24. When thedoors are closed, these parts, including the connection of the door Itwith the cap ll, serve to resist tensile stresses on the lower side ofthe sponson and compression stresses on its upper side as set forth inmy aforesaid co-pending application, for which reason no claim theretois made herein.

The door I2 is connected to the mounting 9 by pairs of telescopicallyrelated members, each pair consisting of a pitman 42 pivotally mountedon a stud shaft 24 carried on the adjacent rod 2d and a cylinder 42apivotally connected at its outer end on the door I2, the inner end ofthe pitman being provided with a head engaging a spring within thecylinder between the head and inner end of the cylinder. The door H isconnected to each end of the mounting 9, each connection comprising alever lla pivoted intermediate its ends on the adjacent stud shaft 24'and a pair of telescopically related members Mb, 410,

having a compression spring between them, similar in construction to themembers 42, 42a. The .outer end of the cylinder 410 is pivotallyconnected to the door ll, whereas the outer end of the pit,- man Mb ispivotally connected to the .outer end of the lever did. The opposite endof the lever Ilia is arranged to engage a stop Md carried by the wall ofthe compartment, whereby the door is moved away from the mounting 9 whenthe latter is moved to its operative position. No claim is made to theseconnections as they form the subject-matter .of my aforementionedco-pending application.

Figs. '7 to 10, inclusive, illustrate a modified form of construction ofthe power means, indicated as an entirety at 28', and linkage, in,-dicated as an entirety at 2? for operating the landing gears. In thisform of construction, the power means 28' is located in a chamber 2.8a:provided in the upper floor Ir of the fuselage Ia and operates throughlinkage 21' directly on the mounting 9 to swing it in either direction.The landing gear and its mounting, and the compartment therefor in thesponson 1 and doors for the compartment are similar to like parts shownin Figs. 1 to 6, inclusive, so that a description of these parts neednot be repeated. The linkag 21' is arranged to operate in a verticalplane coincident with the axle I! and at right angles to the shaft IS.The linkage 21' consists of the following: 21a indicates a cylinderhaving a universal joint connection with the inner end of the axle I I.2112 indicates a piston in the cylinder 21a carried on the outer end ofa rod 29. The cylinder 21a and piston 211) are similar in constructionto the cylinder 21a and piston 21b. The inner end of the rod 29' isconnected by a universal joint to a knuckle 43 in which is mounted a pinor shaft 45. Th opposite ends of the shaft 45 extend through knuckles45a provided on the outer ends of a pair of diverging links 45'. Theinner ends of the links 45' are pivotally mounted on a shaft 290supported similarly to the shaft 290. 46 indicates a link having at itsouter end bifurcations mounted-between the knuckle 43 and knuckles 45a.and in alinement therewith on the shaft 45, whereby the link 48 haspivotal connection with the rod 29' and links 4'5. The inner end of thelink 46 is connected to one side of a nut 41 threaded on a feed screw48, which forms one element of the power means 28', one feed screw 48being provided for each landing gear. The feed screws ,48 extend throughthe chamber 28:0 and each is mounted at its opposite ends in suitablebearings, the bearing for the outer end i of each screw 48 being mountedin a bracket 48m carried by the adjacent side wall Ia and the bearingfor the remote end of the feed screw being mounted in the other sidewall la of the fuselage. The power means 28 comprises the following: 49indicates a motor of the gear reduction type supplied with electriccurrent from a suitable source, the motor shaft being provided with aworm 49a in mesh with a gear 50. The gear 50 is fixed to the adjacentend of a shaft supported at its opposite ends in suitable bearings Fila.The gear 50 is arranged adjacent one sid wall la and meshes with a gear52 fixed to the feed screw 48'remote from the motor 49. that indicates agear fixed to the shaft 5| adjacent the other side wall la and in meshwith a gear 52a fixed to the other feed screw 48. In this arrangement itwill be observed that the driven shaft 5! is common to and drivinglyconnected to both screws 48 and that the latter are simultaneouslydriven to swing both landing gears into operative position or into theirretracted position. Each of the feed screws 48 is formed with a collar53 to limit the movement of the adjacent nut 41 when moving in thedirection to swing the adjacent gear 9 into its compartment, the collar53 being positioned to be engaged by the nut. when the landing gearreaches the limit of its movement in the compartment therefor.

From the foregoing description it will be observed that the wheel I3 isflexibly mounted with respect to the shaft l9 about which it and itsmounting swing and the linkage which is operated by the power means toswing the wheel and its mounting from either position, so that in makinga landing stresses transmitted laterally inwardly, vertically, in thedirection of travel and/or where two or more of these components offorces are combined into a resultant, are yieldingly resisted and unduere-bound of the air-' plane prevented.

In this connection it will be noted that the linkage, when in theposition shown in Figs. 1, 2 and '7, forms a truss mounted on theadjacent side wall la of the fu elage to provide a fixed support for theouter end of the compression devices (21711?29 in Fi '1 and ZlaH-ZS inFig. 7) and the frame it forms a truss swingably mounted on the shaftI9, which is supported by the sponson spars I5. In this arrangement thetruss l8, wheel is and mounting 9 for the latter permit lateral bodilymovement of the airplane relative to the ground (see Figs. 11b to 1412,inclusive), that is, the point or points of contact of the wheel withthe ground, which movement is yieldingly retarded and re-bound preventedby the compression devices 21:10. Also, as noted, the wheel is isdirections, namely, vertically or parallel to the fuselage or bothvertically and parallel to the fuselage as shown in Figs. 11b to 14b,inclusive. As shown in these views, the compression devices 279: andpairs of compression devices 23d-23b operate separately or conjointly ineach landing operation, to resist or retard downward and/or forwardmovement of the airplane dependent on its horizontal or inclinedrelation to the ground at the time one wheel or both wheels make contacttherewith. Accordingly, it will be seen that by connecting the wheelthrough the compression devices within and between two fixed points ofsupport, namely, the universal joint (29a in Fig. 1 or joint 44 in Fig.7) and the shaft l9, forces, due to the momentum and weight of theairplane and its load, if any, transmitted through the wheel to thelanding surface in any direction or the resultant of components offorces in two or more directions, wil1 be adequately yieldingly resistedand abnormal re-bound prevented. As diagrammatically shown in Figs. 11?)to 141), inclusive, the shaft 19 and universal joint 29a have a fixedrelation in all positions of the compression devices 21m, Zea-23 b, fromwhich it follows that in all landing operations the airplane bodilymoves relative to the landing surface about the point or points ofcontact of the wheel [3 therewith vertically (as indicated at d in Fig.15) horizontally (as indicated at e in Fig. 15) or both vertically andhorizontally.

The movements above referred to will be understood from the diagrammaticviews shown in Figs. 11 to 15, inclusive. In these views, Fig. 11 showsthe wheel l3, mounting 9, truss I8 and shaft 19 in side elevation andFig. lla'shows these parts and the compression devices 21x. in frontelevation, all in normal position with the wheel-engaging the ground g.Fig. llb shows a landing operation on'one wheel wherein the pistons inthe front and rear members 23 and piston 21b have beenforced downwardlysubstantially equal distances. Figs. 12 and 12a illustrate a landingoperation where the pistons 23a for the forward members- 23- are forced'downwardly whereas the pistons 23a for the rearward members 23' remainin normal position. Fig. 1% illustratesa condition wherein the devices23' are positioned as shown in Fig. 12, but the piston 21b has beenforced downwardly. In Fig. 12 the pistons for the forward devices 23'are in normal position whereas the pistons in the rearward devices 23have been forced downwardly. In Fig. 13a, the pistons 23a have beenforced downwardly, whereas the piston 2'") remains in normal position.Fig. 14 shows a condition where all of the pistons 23a have been forceddownwardly. Fig. 14a shows acondition where the pistons 23a are forceddownwardly as shown in Fig. 14 and piston 2'") remains in normalposition, whereas Fig. 141) shows a condition 'similar to that in Fig.14a except that the piston 211) has been forced downwardly.

To those skilled in the art to which my invention relates many changesin construction and widely differing embodiments and applications of theinvention will suggest themselves without departing from the spirit andscope thereof. My disclosures and the description herein are purelyillustrative and are not intended to be in any sense limiting.

What I claim is:

1. In an airplane, the combination with a fuselage having at oppositesides thereof wing structures each consisting of an airfoil and asponson formed" with a compartment, of a shaft mounted in saidcompartment transversely of the adjacent'sponson, a landing gearconsisting of a wheel, a frame. swingable about said shaft and resilientsupporting means between the axle for said wheel and said frame, andmeans for swinging said landing gear about said shaft, said swingingmeans consisting of a power mechanism having a thrust member movable inthe plane coincident with the axle for said wheel and linkage betweensaid thrust member and the axle for said wheel and 'swingabl'e in saidplane, said linkage being co-operable with said shaft to support saidlanding gear in said compartment and operable to swing it to operativeposition, one of the links of said linkageconsisting of resilientlyrelated elements.

2. In an airplane, the combination with a fuselage having at; opposite;sides thereof wing structures, each consisting of an airfoil and asponson, said fuselage and sponson being formed with alinedconnectedcompartments, of a shaft longitudinally mounted in thecompartment in said sponson, a separate shaft mounted on the adjacentside wall ofsaid fuselage in parallel relation to said first mentionedshaft, a landing gear fitting into th compartment in'said sponson andconsisting of a frame swingably mounted on said first mentionedshaft anda wheel mounted in said frame, power means including a feed screwmounted in the compartment of said fuse- 'lage and a nut threaded onsaid screw, a pair of spaced links mounted at their inner ends on saidseparate shaft, and linkage pivotally connected to said nut, the outerends of said spaced links and the axle for said wheel arranged to 'beoperated by said power means to swing said landing gear from thecompartment in said sponson into operative position and in the oppositedirection.

3. An airplane as claimed in claim 2 wherein resiliently related devicesare interposed between said linkage and the axle for said wheel.

4. In an airplane, the combination with a fuselage having at oppositesides thereof wing structures each formed with a compartment, of a shafttransversely mounted in said compartment, a landing gear consisting of awheel, a truss swingably mounted on said shaft and resilient supportingmeans between the opposite ends of the axle for said wheel and adjacentsides of said truss, and means for swinging said landing gear about saidshaft, said swinging means comprising a power mechanism and linkagebetween said power means and the axle for said wheel-and co-operablewith said shaft to support said landing gear in said compartment andoperable to swing it to operative-positiomsaid linkage consisting ofrelatively movable, compression devices the outer one ,of which has auniversal joint connection at its outer end with the inner end of theaxle for said wheel, upper and .lower links swingable relative to saidfuselage and eachother on axes parallel to said shaft, a universal jointfor connecting the uterendsof said links and the inner end of the othercompression device together and an operating con nection between theupper link and said power means, said upper and lower links forming atruss when said landing gear is moved into operativc position. r

5. In an airplane, the combination with a fuselage having at oppositesides thereof wing structures each formed with a compartment, of a shafttransversely mounted in said compartment, a landing gear consisting of awheel, a truss swingably mounted on said shaft and resilient supportingmeans between the opposite endsof the axle for said wheel and adjacentsides of said truss, and means for swinging said landing gear about saidshaft, said swinging means comprising'a power mechanism and linkagebetween said power means and the axle for said wheel and co-operablewith said shaft to support said landing gear in said compartment andoperable to" swing it to operative position, said linkage consisting ofrelatively movable compression devices the outer one of which has auniversal joint connection at its outer end with the inner end of theaxle for said wheel, a lower link pivotally mounted at its inner end onsaid fuselage to swing on an axis parallel to said shaft, an upperlink-pivotally connected at its inner end to an element of said powermeans .and a universal joint for connecting the outer ends of said linksand the inner end of the other compression. de-. vice together, saidupper and lower links forming a' truss when said landing gear is movedinto operative position.

6. In an airplane, the combination with a fuselage havingat oppositesides thereof wing structures each formed with a compartment, of a shafttransversely mounted in said compartment, a landing gear consisting of awheel, a truss swingably mounted on said shaft and resilient supportingmeans between the opposite end of the axle for said wheel andadjacentsides of said operable with said shaft to support said landing gear insaid compartment and operable to swing it to operative position, saidlinkage consisting of relatively movable compression devices the outerone of which has a universal joint connection at its outer end with theinner end of the axle for said wheel, a lower link pivotally mounted onsaid fuselage on an axis parallel to said shaft, inner and outerpivotally connected link elements, the outer end of the inner elementbeing pivotally mounted on said fuselage on an axis parallel to saidshaft, a universal joint for connecting the outer ends of said link andouter element and inner end of the other compression device together anda link for connecting an element of said power means to one of said linkelements, said link and said link elements forming a truss when saidlanding gear is moved into operative position.

7. In an airplane, the combination with a fuselage having at oppositesides thereof wing structures each formed with a compartment, of a shafttransversely mounted on the side wall of said fuselage, a separate shaftparallel to said first mentioned shaft transversely mounted in said comartment, a landing gear comprising a truss mounted on said separateshaft, a wheel, pairs of compression devices on opposite sides of saidwheel and connected to the opposite ends of the axle therefor andopposite ends 'of said truss for supporting said wheel on said truss ina plane cutting the axis of said separate shaft, compression elementsthe outer one of which has a universal joint connection with the innerend of the wheel axle and a truss between said fuselage and the outerend of the other compression element and connected to the latter by auniversal joint, the last mentioned truss consisting of a linkage, onelink thereof being mounted on said first men- 14 tioned shaft, and powermeans connected to another link of said linkage for operating the latterto swing said landing gear into said compartment.

8. In an airplane, the combination with a fuselage having at oppositesides thereof wing structures each formed with a compartment, a shaft insaid compartment disposed transversely of the adjacent wing structure, atruss swingably mounted on said shaft, a separate truss mounted on theside wall of said fuselage, a landing Wheel, pairs of compressiondevices between the axle of said wheel and said first mentioned truss,compression devices between and having universal joint connection withthe inner end of the wheel axle and said separate truss, saidcompression devices providing for movements of said wheel vertically,laterally and transversely relative to the adjacent wing structure, saidseparate truss consisting of a linkage swingable in a plane at rightangles to said shaft, and power means connected to one link of saidlinkage for operating it to swing said wheel into said compartment.

EDWARD E. WALLACE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,874,570 Minshall Aug. 30, 19322,187,040 Laddon et a1 Jan. 16, 1940 1,968,637 Dornier July 31, 19341,718,189 Baumann June 18, 1929 2,220,546 Saulnier Nov. 5, 19401,866,534 J anin July 12, 1932 2,115,701 Baer et al May 3, 19381,890,553 Young -1 Dec. 13, 1932 FOREIGN PATENTS Number Country Date819,026 France June 28, 1937

